La Copita Ranch Research Team
Dr. Paul Barnes

Paul W. Barnes, Ph.D. Professor Phone: 512-245-3753 Fax: 512-245-8713 E-mail: pb03@swt.edu

Mailing Address

Department of Biology
Southwest Texas State University
601 University Drive
San Marcos, TX 78666

Research Interests

My research interests include various aspects of the functional ecology of plants, plant populations and plant communities. I am especially interested in the ecology of grasslands and savannas, mechanisms of resource competition and facilitation between plants, plant carbon and water relations, plant responses to ultraviolet (UV-B) radiation, and the ecological consequences of stratospheric ozone depletion.

At the present time, the research in my lab is focused on two specific projects: 1) The physiological and ecological effects of stratospheric ozone depletion and the changing solar ultraviolet-B radiation (UV-B; 280-320 nm) climate on plants and vegetation, and 2) Facilitation, competition and woody plant increase in Texas savanna ecosystems. These projects involve significant collaboration with individuals from other universities and institutions, and have involved undergraduate students, graduate students, technicians and postdoctoral research associates in various capacities. Funding support for these projects has come from grants from the NSF, USDA and SWT.

• UV-B Research
• Savanna Ecology Research
• Research Opportunities
• SWT Freeman Ranch

Publications

Nelson, J.A., P.W. Barnes, and S. Archer. 2001. Leaf demography and growth responses to altered resource availability in woody plants of contrasting leaf habit in a subtropical savanna. Plant Ecology. In Press.

Barnes, P.W., S.-Y. Liang, K.E. Jessup, L.E. Ruiseco, P.L. Phillips, and S.J. Reagan. 2000. Soils, topography and vegetation of the Freeman Ranch. Freeman Ranch Publication Series No. 1-2000. Southwest Texas State University Press, San Marcos, TX.

Barnes, P.W., P.S. Searles, C.L. Ballare, R.J. Ryel, and M.M. Caldwell. 2000. Non-invasive measurements of leaf epidermal transmittance of UV radiation using chlorophyll fluorescence: field and laboratory studies. Physiologia Plantarum 109: 274-283.

Barnes, P.W., and S. Archer. 1999. Tree-shrub interactions in a subtropical savanna parkland: competition or facilitation? Journal of Vegetation Science 10: 525-536.

Caldwell, M.M., P.S. Searles, S.D. Flint, and P.W. Barnes. 1999. Terrestrial ecosystem responses to solar UV-B radiation mediated by vegetation, microbes and abiotic photochemistry. pp. 241-262, In: M. Press, J. Scholes and M. Barker (eds.), Physiological Plant Ecology. Blackwell Science, Oxford.

Gass, L., and P.W. Barnes. 1998. Microclimate and understory structure of live oak (Quercus fusiformis) clusters in central Texas, USA. The Southwestern Naturalist 43: 183-194.

Barnes, P.W., and S. Archer. 1996. Influence of an overstory tree (Prosopis glandulosa) on associated shrubs in a subtropical savanna parkland: implications for patch dynamics. Oecologia 105: 493-500.

Barnes, P.W., C.L. Ballaré, and M.M. Caldwell. 1996. Photomorphogenic effects of UV-B radiation on plants: consequences for light competition. Journal of Plant Physiology 148: 15-20.

Barnes, P.W., S.D. Flint and M.M. Caldwell. 1995. Early-season effects of supplemented solar UV-B radiation on seedling emergence, canopy structure, simulated stand photosynthesis and competition for light. Global Change Biology 1: 43-53.

Ballaré, C.L., P.W. Barnes and S.D. Flint. 1995. Inhibition of hypocotyl elongation by ultraviolet-B radiation in de-etiolating tomato seedlings. I. The photoreceptor. Physiologia Plantarum 93: 584-592.

Ballaré, C.L., P.W. Barnes, S.D. Flint and S. Price. 1995. Inhibition of hypocotyl elongation by ultraviolet-B radiation in de-etiolating tomato seedlings. II. Time course, comparison with flavonoid response and adaptive significance. Physiologia Plantarum 93: 593-601.

Barnes, P.W., S. Maggard, S.R. Holman and B.S. Vergara. 1993. Intraspecific variation in sensitivity to UV-B radiation in rice. Crop Science 33: 1041-1046.

Dai, Q., V.P. Coronel, B.S. Vergara, P.W. Barnes, and A.T. Quintos. 1992. Ultraviolet-B radiation effects on growth and physiology of four rice cultivars. Crop Science 32: 1269-1274.

Ballaré, C.L., P.W. Barnes, and R.E. Kendrick. 1991. Photomorphogenic effects of UV-B radiation on hypocotyl elongation in wild-type and stable-phytochrome-deficient mutant seedlings of cucumber. Physiologia Plantarum 83: 652-658.

Bachelet, D., P.W. Barnes, D. Brown, and M. Brown. 1991. Latitudinal and seasonal variation in calculated ultraviolet-B irradiance for rice-growing regions of Asia. Photochemistry and Photobiology 54: 411-422.

Barnes, P.W., S.D. Flint, and M.M. Caldwell. 1990. Morphological responses of crop and weed species of different growth forms to ultraviolet-B radiation. American Journal of Botany 77: 1354-1360.

Ryel, R., P.W. Barnes, W. Beyschlag, M.M. Caldwell, and S.D. Flint. 1990. Plant competition for light analyzed with a multispecies canopy model. I. Model development and influence of enhanced UV-B conditions on photosynthesis in mixed wheat and wild oat canopies. Oecologia 82: 304-310.

Beyschlag, W., P.W. Barnes, R. Ryel, M.M. Caldwell, and S.D. Flint. 1990. Plant competition for light analyzed with a multispecies canopy model. II. Influence of photosynthetic characteristics on mixtures of wheat and wild oat. Oecologia 82: 374-380.

Barnes, P.W., W. Beyschlag, R. Ryel, S.D. Flint, and M.M. Caldwell. 1990. Plant competition for light analyzed with a multispecies canopy model. III. Influence of canopy structure in mixtures and monocultures of wheat and wild oat. Oecologia 82: 560-566.

Barnes, P.W., H. Gucinski, and D. Turner. 1989. Ecosystem responses to increases in solar ultraviolet-B radiation. Air and Waste Management Association, Annual Meeting Published Preprint 89-5.6.

Barnes, P.W., P.W. Jordan, W.G. Gold, S.D. Flint, and M.M. Caldwell. 1988. Competition, morphology and canopy structure in wheat (Triticum aestivum) and wild oat (Avena fatua) exposed to enhanced UV-B radiation. Functional Ecology 2: 319-330.

Beyschlag, W., P.W. Barnes, S.D. Flint, and M.M. Caldwell. 1988. Enhanced UV-B irradiation has no effect on photosynthetic characteristics of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.) under greenhouse and field conditions. Photosynthetica 22: 516-525.

Barnes, P.W., S.D. Flint, and M.M. Caldwell. 1987. Photosynthesis damage and protective pigments in plants from a latitudinal arctic/alpine gradient exposed to supplemental UV-B radiation in the field. Arctic and Alpine Research 19: 21-27.

Keeler, K.H., B. Kwankin, P.W. Barnes, and D.W. Galbraith. 1987. Polyploid polymorphism in Andropogon gerardii. Genome 29: 374-379.

Barnes, P.W. 1986. Variation in the big bluestem (Andropogon gerardii)-sand bluestem (Andropogon hallii) complex along a local dune/meadow gradient in the Nebraska sandhills. American Journal of Botany 73: 172-184.

Barnes, P.W. 1985. Adaptation to water stress in the big bluestem - sand bluestem complex. Ecology 66: 1908-1920.

Barnes, P.W., A.T. Harrison, and S.P. Heinisch. 1984. Vegetation patterns in relation to topography and edaphic variation in Nebraska Sandhills Prairie. Prairie Naturalist 16: 145-158.

Barnes, P.W., L.L. Tieszen, and D.J. Ode. 1983. Distribution, production and diversity of C-3 and C-4 dominated communities in a mixed prairie. Canadian Journal of Botany 61: 741-751.

Tieszen, L.L., D.J. Ode, P.W. Barnes, and P.M. Bultsma. 1983. Seasonal variation in C-3 and C-4 biomass at the Ordway Prairie and selectivity by bison and cattle. Proceedings of the Seventh North American Prairie Conference, Springfield, MO, 1980. pp. 165-174.

Barnes, P.W., and A.T. Harrison. 1982. Species distribution and community organization in a Nebraska Sandhills mixed prairie as influenced by plant/soil-water relationships. Oecologia 52: 192-201.